In my case, I was thinking of people like the Vlogbrothers, Neil Gaiman and especially Amanda Palmer. Neil and Amanda know they're part of my story, but to what extent? I mean, also, they were part of it way back, before I'd met them in person. And what about people you do know, but they might not know how much they've influenced you?
What I'm thinking is this: we're all the main character in our stories, but the secondary characters vary and might not even know they rank there you know? And you may not be a secondary in their story. You may be background. Or you may be more important than you know. I guess partially i'm making the point that you should think about this in writing--who influenced your character and may never be on stage and to whom your character is an important secondary--but I was really focusing more on real life application.
Like, be careful how you treat people, because you never know if you're important in their story.